[CoaPsyFactor]

With this function you can easily find is some player near some other player, it is simple to use.

pawn Код:

IsPlayerNearPlayer(playerid, n_playerid, Float:radius){
    new Float:npx, Float:npy, Float:npz;
    GetPlayerPos(n_playerid, npx, npy, npz);
    if(IsPlayerInRangeOfPoint(playerid, radius, npx, npy, npz)){
        return true;
    }else{
        return false;
    }
}

Usage:

pawn Код:

forward IsPlayerNearPlayer(playerid, n_playerid, Float:radius);
IsPlayerNearPlayer(playerid, n_playerid, Float:radius){
    new Float:npx, Float:npy, Float:npz;
    GetPlayerPos(n_playerid, npx, npy, npz);
    if(IsPlayerInRangeOfPoint(playerid, radius, npx, npy, npz)){
        return true;
    }else{
        return false;
    }
}
public OnPlayerCommandText(playerid, cmdtext[]){
  new idx, cmd[256];
  cmd = strtok(cmdtext, idx);
  if(strcmp(cmd, "/near")){
    if(IsPlayerNearPlayer(playerid, 5, 10.0)){
      SendClientMessage(playerid, COLOR_WHITE, "You are near player with id 5 Radius is 10");
      return 1;
    }else{
      SendClientMessage(playerid, COLOR_WHITE, "You are NOT near player with id 5 Radius is 10");
      return 1;
    }
  }
}

So as you can see, with this function we can check is player with example id 5 near player that called command /near